The fine structure of the sense organs of the cephalopod mollusc Nautilus

Summary The structure of the rhinophore, digital tentacles, post-ocular tentacles and the eye of Nautilus macromphalus are described. The rhinophore is composed of mucous cells, ciliated cells, and flask-shaped ciliated cells. The latter are probably olfactory receptors. The digital tentacles are composed of mucous cells and pigmented cells. Motor-end-plates found in the muscle layer below the epithelium of the digital tentacles are similar to those described in other cephalopods. The post-ocular tentacle contains receptor cells that bear macrocilia. These may be mechanoreceptors. The retina is composed of retinula cells and supporting cells. A complex rhabdom is formed at the distal ends of the retinula cells. The supporting cells send processes up between these rhabdoms. Both types of cells contain pigment granules but the retinula cell has a complex membranous structure in its perikaryon. No synapses were found at the bases of the retinula cells. At the side of the retina are mucous cells that are presumed to produce the jelly-like substance that fills the inside of the eye in life. The likely function of the eye is discussed and it is suggested that it is capable of simple discriminations. It is suggested that the sense organs are probably comparatively unchanged from those of fossil nautiloids. Acknowledgements. This paper is dedicated to the late Dr. Yves Merlet who collected the nautiluses used in this study.We would like to thank Prof. J. Z. Young for all his support and encouragement. The Royal Society, The Percy Sladen Memorial Fund, and University College, London, provided the financial support that enabled one of us (V.C.B.) to collect nautiluses. The Science Research Council, U.K., provided the electron microscope used in the major part of the study and a grant to one of us (V.C.B.). We would also like to thank Prof. J. B. Gilpin-Brown who provided Fig. 1, Dr. R. Catala, for aquarium facilities, Mr. M. P. Legand and the Institut Français d'Oceanie, Noumea, New Caledonia, for laboratory facilities, Dr. J.-M. Bassot and Dr. Anna Bidder for advice on catching and preserving nautiluses, Mrs. Judy Parkes and Mr. M. Barker for photographic assistance, and Miss J. Date for secretarial assistance.     

Metabolic Response to Oral Glucose in Healthy South African White,Indian, and African Subjects

The response of serum insulin, growth hormone, plasma free fatty acids, triglycerides, and blood glucose to an oral glucose load was investigated in healthy White, African, and Indian subjects. Serum cholesterol, uric acid, platelet adhesiveness, and urine insulin clearance were also measured. Each racial group responded differently. Most striking were the differences between Africans and Whites; despite similar mean blood glucose values at all times during the test, the Africans had lower serum insulin levels, a lower urine insulin clearance, a much greater rise of growth hormone, a more definite and prolonged suppression of free fatty acid release, lower serum cholesterol and uric acid levels, and a trend towards lower plasma triglyceride values.The Indians tended to resemble Whites rather than Africans with respect to their insulin, growth hormone, cholesterol, and triglyceride levels. Their glucose tolerance was decreased compared with that of the other two groups, but suppression of their free fatty acids was enhanced. Platelet adhesiveness was similar in all three groups.The reasons for these differences are unknown, but must be related to genetic and environmental differences among the three races.     

Acute Paracetamol Poisoning

Of 41 cases of acute paracetamol poisoning one died of gastrointestinal haemorrhage and acute massive necrosis of the liver, three became jaundiced, and 13 others had biochemical evidence of hepatocellular damage. Liver damage is a toxic effect which is present in most patients who ingest more than 15 g. of paracetamol. One patient with liver damage survived renal failure due to acute tubular necrosis. It is suggested that the renal lesion was also the result of paracetamol overdosage.Profound hypoglycaemia and metabolic acidosis may also complicate severe poisoning. Plasma levels of para-aminophenol fall rapidly, and procedures currently used to enhance the elimination of the drug cannot be expected to prevent development of hepatic damage.     

Cortisol and Growth Hormone Secretion in Relation to Linear Growth: Patients with Still's Disease on Different Therapeutic Regimens

Linear growth was studied in 20 children suffering from Still''s disease on various treatment regimens, and their ability to secrete growth hormone and cortisol was investigated. Growth recovered on reducing daily corticosteroid therapy or on changing to an alternative regimen. Retardation of growth was not due to an absolute inability to secrete growth hormone. Basal plasma cortisol levels and the plasma cortisol response to hypoglycaemia were reduced in patients on daily steroid therapy, but patients on alternate-day prednisone did not differ significantly in this respect from those on non-steroid regimens. Those on alternate-day corticotrophin showed preservation of the circadian rhythm but a subnormal response to hypoglycaemia.     

Metabolism of Peptides by Rumen Microorganisms

Rumen microorganisms utilize tryptic peptides from Chlorella protein, forming carbon dioxide, volatile fatty acids, and bacterial protein. Peptide carbon is more efficiently converted into bacterial protein than is amino acid carbon. A progressive degradation of the peptides was demonstrated by use of columns of Sephadex G-25.